CODEWITHSUNDEEP
pythonjson
Razzaghnoori
Razzaghnoori

Reputation: 374

Is there a better way to access deeply nested JSON-like objects in Python?

I often have to deal with accessing deeply nested JSON responses. One way to access an element could be something like this:

json_['foo'][0][1]['bar'][3]

But that's obviously not at all safe. One solution is to use the get method of Python dict and pass {} as the default argument.

json_.get('foo', {})[0][1]['bar'][3]

But that again can raise an IndexError exception which leaves me with a length check for every list element access.

target = json_.get('foo', {})
if not target:
   return
target = target[0]
if len(target) < 2:
   return
target = target[1].get('bar', {})
if len(target) < 4:
   return
target = target[3]   #Finally...

And that's not at all pretty. So, is there a better solution for this?

Upvotes: 1

Views: 601

Answers (2)

RoadRunner
RoadRunner

Reputation: 26335

Adding to the other answer, if you want to just ignore the exceptions you could use:

# Wrap this in a function
try:
    return json_['foo'][0][1]['bar'][3]
except (KeyError, IndexError):
    pass

Addtionally, another way is to suppress exceptions is with contextlib.suppress():

from contextlib import suppress

# Wrap this in a function
with suppress(KeyError, IndexError):
    return json_['foo'][0][1]['bar'][3]

Upvotes: 1

Barmar
Barmar

Reputation: 782315

Just wrap the entire thing in try/except:

try:
    return json_['foo'][0][1]['bar'][3]
except IndexError, KeyError:
    return None

Upvotes: 6

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